Going more than a day between dialysis sessions may boost a multitude of health risks for end-stage renal disease patients, a national study showed.

Action Points

Note that most ESRD patients receiving maintenance hemodialysis in the U.S. are exposed to dialysis three days per week, with two one-day intervals and one two-day interval between sessions.

Point out that this retrospective study found that rates of all-cause mortality, deaths from cardiac causes and infection, as well as hospital admissions for cardiovascular events, were significantly elevated after the two-day interval.

Going more than a day between dialysis sessions may boost a multitude of health risks for end-stage renal disease patients, a national study showed.

Overall mortality and death from cardiac causes, cardiac arrest, myocardial infarction, and infections were significantly elevated after the two-day interval on a three-times-a-week dialysis schedule, Robert N. Foley, MB, of the U.S. Renal Data System and University of Minnesota in Minneapolis, and colleagues found.

Compared with one-day intervals between dialysis the rest of the week, hospital admissions for a range of cardio- and cerebrovascular events were also up following the two-day interval, the group reported in the Sept. 22 issue of the New England Journal of Medicine.

Most dialysis patients around the world get their maintenance treatments three times a week, usually taking off weekend days for the two-day interval that schedule entails.

But it may be reasonable for patients to request a dialysis schedule that eliminates the two-day interval, Foley noted in an email to MedPage Today.

"The typical practice of three-times [weekly] was never established on the basis of a trial," he explained. "As no definitive evidence exists for any schedule, a case-by-case approach is reasonable."

Concern over that gap in dialysis has raised interest in daily hemodialysis, which a growing number of centers are offering, Foley's group noted.

With these national results and those of other studies suggesting elevated sudden death and cardiac arrest risk at the end of the long interdialytic interval, there's equipoise to do a controlled trial comparing dialysis schedules, they argued.

Nothing has yet been conclusively shown in a randomized controlled trial to reduce the high cardiovascular and mortality risk for hemodialysis patients, the researchers pointed out.

Foley's group examined outcomes among the 32,065 end-stage renal disease patients on thrice-weekly hemodialysis who were included in the nationally-representative sample of the End-Stage Renal Disease Clinical Performance Measures Project from 2005 through 2007.

Comparing event rates over the mean follow-up of 2.2 years, all-cause mortality rates were highest on the day of the hemodialysis session after the long, two-day interval. Mortality then largely evened out on the other days of the week.

Admissions for any cardiovascular event followed a sawtooth pattern: highest on the day after the two-day interval but rising after each one-day interval as well.

The mortality risks associated with the long interval versus other days (in deaths per 100 person-years) were significant for:

All-cause mortality (22.1 versus 18.0, P<0.001)

Death from cardiac causes (10.2 versus 7.5, P<0.001)

Infection-related mortality (2.5 versus 2.1, P=0.007)

Cardiac arrest deaths (1.3 versus 1.0, P=0.004)

Mortality from myocardial infarction (6.3 versus 4.4, P<0.001)

The risk of going to the hospital on the day after the long interdialytic interval compared with other days, also per 100 person-years, was significant for admissions related to the following:

MI (6.3 versus 3.9, P<0.001)

Congestive heart failure (29.9 versus 16.9, P<0.001)

Stroke (4.7 versus 3.1, P<0.001)

Dysrhythmia (20.9 versus 11.0, P<0.001)

Any cardiovascular event (44.2 versus 19.7, P<0.001)

"Subgroup analyses suggested that this excess of adverse events on the day after the long interdialytic interval was close to being a generalized phenomenon," the group noted.

They cautioned that their database couldn't determine when events that occurred after an interval happened in relation to dialysis that day, nor could it account for missed or shortened dialysis sessions.

Other limitations included the nonexperimental, retrospective design and reliance on administrative codes to identify cardiovascular events as well as lack of cost data, they noted.

Also, "given that hospitalization is very costly in the dialysis population, it might be relevant to compare the upstream costs of an extra dialysis session every two weeks with the downstream costs associated with the use of other health care resources," they wrote.

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